Keto shampoos shouldn't be used daily. That's terrible for your scalp.
Try Regenepure DR. It's got 1% Keto instead of 2% and it contains other beneficial ingredients so it's a lot less harsh. A lot of people buy DR + NT together
Amazon link, DR is the hair loss shampoo while NT is the one that contains all the beneficial stuff like saw palmetto. You're supposed to alternate the two, DR one day and NT the next. It's way more expensive than Nizoral though.
Saw palmetto is not a mild version of propecia, not according to any real studies anyway. If you are worried your dick might go soft you can start with topical Minoxidil on top of the shampoo. Honestly I don't think Keto shampoos do all that much.